During the this
period the Polish-Lithuanian
Commonwealth was the largest territory in central and eastern Europe.
Together they stretched from the Baltic to the Black Sea nd from
The Holy Roman Empire almost to the gates of Moscow.

Its army, though
comparatively small for such a large country, achieved many successes
against a wide variety of aggressive foes. There
were few years in this era when Polish-Lithuanian forces were not
fighting against one of the Commonwealth's enemies, which included
Tartars, Teutonic Knights, Swedes, Austrians, Ottomans, Muscovites,
Moldavians and Zaporozhian Cossacks.

Their forces combined elements of eastern
tactical and strategic thinking with western tactics of technology
and firepower and the influence of the Polish army on the West is
often under estimated, for example:-

It should be remembered that one of the greatest
generals in history, Gustav Adolf, developed his skills in almost
continuous warfare with the Poles - and his success in the Thirty
Years War was preceded by many years of effort against inferior
numbers of Poles who had humiliated the Swedish army at Kircholm.